AMD 8xxx & 9xxx CPU Bus Overclocking

[Kanoe]

Most of the overclocks people do these days is purely just turning up the multiplier on their CPU's. Its a quick and easy to process to achieve higher clocks, sure.

But it seems that the CPU Bus overclock is becoming a bit of a dying art. I thought it might be interesting to know what other 8xxx & 9xxx CPU users did for their overclocking and what kind of numbers they got for their Bus speed.

Some useful information would be:

- CPU model (eg 8350)
- Bus speed (base clock is 200MHz)
- Did you try overclocking the Bus speed? If not, why not?

 

[Hagar]

FX8350
300MHz Bus clock.

This gives 4800 at x16 and a ram clock of 2GHz.
302 x 16 gave me the highest GFlops in IBT, more than higher frequencies.
Image from January 2013

I am currently running 4200 (x14) though, as I am not using the PC for much.

 

[ALXAndy]

On FX chips the bus is the best way to clock. Adding multi needs a ton of voltage.

I managed this on mine, 24/7 stable.



'only' 1.465v. I couldn't even get 4.2ghz on multi alone.

 

[Kanoe]

Good stuff guys.

I never managed to get my multiplier up from default no matter how much voltage I put through it.

Also couldn't get any other bus speed over base other than 280. Makes my memory speed a bit odd though.

 

[adolf hamster]

hmmm, andy if your right then i guess i'll have to try that, not sure how much my ram will agree though.

 

[Kanoe]

Only just noticed my Rated FSB, dont know how I've got it at 3371MHz!!!

 

[Hagar]

Only just noticed my Rated FSB, dont know how I've got it at 3371MHz!!!

That would not help, probably bios doing auto. Set it in the range 2000 / 2800.

I see you have a later stepping 2. When did you buy this chip? Mine was a preorder purchase. Not sure if any different.

 

[JonSmith]

How the hell is that even booting at that FSB speed?!?

 

[ALXAndy]

How the hell is that even booting at that FSB speed?!?

The ROG version is way older than the actual latest CPUID. It reports incorrectly basically.

 

[Kanoe]

I'll put on the actual latest CPUID tonight to see what it says, does seem unrealistic.

 

[ALXAndy]

I'll put on the actual latest CPUID tonight to see what it says, does seem unrealistic.

CPUID can do weird stuff on older versions tbh.

 

[Kanoe]

Confirmed!

CPUID v1.70 (newest I could find on their website)

 

[Tuvoc]

I'm just using the multiplier for a modest overclock at stock volts. It is the lazy way for sure, but it means the CPU is the only thing overclcoked and saves lots of time on stabilty testing.

 

[Damo667]

ive got a stable overclock at 4.8ghz @1.524v on cpuz

240 x 20
memory- 1599mhz
nb- 2160mhz
ht- 2400mhz

i cant run that in this weather tho it hits the thermal limit after a couple of minutes. my oc for the summer is a simple 4.5ghz stock voltage multiplier only, 1866mhz memory, 2400mhz nb and 2600mhz ht.

 

[Tuvoc]

Does your more conservative summer overclock feel any slower ?

 

[Damo667]

Does your more conservative summer overclock feel any slower ?

ive not rendered any videos with it at 4.8ghz but gaming and general use i cant tell a difference tbh. im no expert tho by any means. id like to bring it up into my room where its 16-18 deg c 24/7 and try it but it weighs an absolute tonne.